This invention relates to handling of materials in layers, and especially in layers on pallets and other supporting surfaces. It relates to palletizing materials with a minimum amount of manual lifting of product or other load materials by attending labor or machine operators. Individual elements of material being handled may be thin as a single sheet of paper, or thicker such as a magazine, a book, or a conventional carton of product. Particularly with reference to cartons and other boxes, the individual elements are sometimes susceptible to lateral displacement relative to each other in a layer, especially where there are gaps in rows, or between rows.
Individual layers on a pallet are typically separated by separating sheets, typically referred to as tie sheets. This invention is particularly concerned with the handling of separating sheets which are formed and used as 3-dimensional caps over each layer. Such a cap has a main panel covering the layer, and a plurality of edge panels depending downwardly from the main panel and engaging the sides of the respective layers. The cap is conventionally used to cover, in combination, a plurality of open-topped cartons which form a palletized layer of such cartons. Such cap is also used to cover an entire layer for the purpose of providing lateral stability to a palletized layer of unstable product such as e.g. a palletized layer of empty 2-liter polyethylene terephthalate soft drink bottles. Typically, the above caps are shipped to the user set up in 3-dimension format, and are placed on the pallet by hand labor. The use of hand labor for such repetitious task is wasteful of manpower. It is also wasteful to ship the caps set up if they can be shipped flat and automatically set up by the user in the palletizer.
Apparatus for automatically palletizing layers of material is known in the art. A conventional palletizer for boxes or cartons may use a horizontally, reciprocally movable transfer plate for carrying boxes to a position above a pallet onto which the boxes are to be loaded. The transfer plate is then withdrawn from beneath the boxes, thereby depositing them onto the pallet. Retaining means are used for preventing the boxes from moving with the transfer plate as it is withdrawn. Such retaining means commonly include a bar which abuts the side of the boxes facing the direction of transfer plate withdrawal. Structures of this general nature are disclosed in, for example, U.S. Pat. No. 3,149,732 Gagnon et al and U.S. Pat. No. 3,833,132 Alduk.
Palletizing and depalletizing apparatus are disclosed in the following U.S. Pat. Nos.
______________________________________ Paxton et al 2,243,919 Samler 2,656,047 Locke 2,875,907 Woodcock 2,875,908 Keyes 2,878,948 Lazott et al 2,937,482 Reed 2,940,617 Freeman 2,978,125 Magnuson 3,105,598 Gagnon 3,149,732 McWilliams 3,157,301 Jeremiah 3,166,203 Kampert 3,257,006 Bruce 3,278,048 Roth et al 3,389,810 Grasvoll 3,594,977 Larson 3,606,310 Brockmuller 3,637,093 Grasvoll 3,648,857 Carlson 3,669,282 Von Gal Jr. et al 3,682,338 Munroe 3,720,176 Alduk 3,833,132 Dawson et al 3,836,018 Golantsev 3,837,140 Ballard 3,884,368 Beal 3,946,883 Wilde et al 3,986,620 Kelley 4,030,618 Mabey et al 4,032,021 Schmitt 4,067,456 Zimmerman 4,159,058 Schmitt 4,162,016 Shorthouse 4,172,686 Schmitt 4,195,959 Pantin 4,205,934 Faltin 4,230,311 Donnelly 4,234,280 Meratti 4,255,074 Pulda 4,339,220 Cox 4,342,531 Sylvander 4,383,788 Ishida et al 4,397,246 Werkheiser 4,422,549 Werkheiser 4,439,084 Wise 4,477,067 Feldkamper 4,671,723 Liebel 4,708,247 as well as Fed. Rep. of Germany 3,107,495 Japan 54,129661 ______________________________________
So far as is known to the inventors herein, none of the above references teach any apparatus or method adapted to automatically place a cap on a formed layer on a pallet. Neither does any reference teach apparatus or method for forming a cap as an integral part of the palletizing process.
It is an object of this invention to provide palletizing apparatus including means to automatically form and place caps on layers in the formation of pallet loads.
It is another object to provide apparatus and methods to preform the caps from flat sheets and to place the pre-formed caps on the respective layers of material.
It is yet another object to provide apparatus and methods to place the flat sheets, adapted to being formed into caps, on the layers, in the pallet load, and subsequently to form the flat sheets into layer caps in the pallet load.
It is still another object to provide apparatus and methods adapted to form the flat sheets into layer caps in the pallet load, and to hold each so-formed cap in its formed configuration until the formed configuration is secured by stretch wrapping.